In modern distributed enterprises, designers in multiple remote locations must review designs during meetings. A number of remote participants often want to visually inspect detailed product designs using digital geometry on a computer. During such meetings, a participant may want to inspect a design for various characteristics, such as detailed part space reservation, interference, excessive gaps, maintainability, manufacturability, alternative configuration comparison, detailed part data, and executive and customer approval. These visual inspections occur with participants in a single meeting space, or in various locations distributed around the globe simultaneously using tools such as Internet connections and teleconferencing.
A design review typically starts by loading a set of 3D geometry models into computer memory. To allow a person to visualize the 3D geometry models, the computer processes the models with rendering algorithms that employ standard CPUs and/or graphics accelerators to produce an image, or frame, on a computer-display screen. The algorithms render the 3D model in a realistic-looking 2D picture that is understandable to many users. To achieve a sense of the 3D nature of the set of models, users are allowed to scale, rotate, and translate the image in real time (around 15 frames per second). What each user sees on his or her screen is limited by the speed of the computer and, for remote users, the network bandwidth. It is highly beneficial for design review continuity to have all participants see the same image at the same time, including dynamic transformation operations in order to conduct real time collaboration.
One method to conduct a simultaneous design review requires distributing copies of data, often gigabytes in quantity, to all remote locations in order to accommodate simultaneous display performance. However, such distribution may not be desirable because of security risks, large storage requirements for remote users, and preparation time. Further, this method is disadvantageous when a disparity in rendering performance on remote user's computers is present. Thus, it is desirable to centrally locate the source data. Another method of conducting simultaneous review involves rendering in a central location and sending only the rendered frame to each user. However, when distances increase and traffic is routed on the general Internet, individual frames are transmitted at unpredictable rates, primarily due to unpredictable variances in network bandwidth for each user. This causes user frustration because of inconsistent rendering speeds and poor interactivity with other users. Another possible method involves reducing the level of detail of the centrally-rendered frames when they are transmitted to remote users. This action may increase image-manipulation and load-time performance but it reduces the effectiveness of the presentation and requires more software complexity. Further, it penalizes users with a greater network bandwidth, as they are only sent the amount of information as the lowest network bandwidth user can process, thus overcompensating the frame resolution reduction for all users except the user with the smallest network bandwidth.
Therefore, it would be advantageous to provide a synchronous display of 3D computer renderings to remote users where the computer rendering is conducted in a central location and where each remote user is able to see as much detail of the centrally-transmitted rendered frames as his or her network bandwidth will permit.